#define  _CRT_SECURE_NO_WARNINGS 1

#include <stdio.h>

int My_F(int n)
{
	int i = 0;
	int M = 1;
	for (i = 1; i <= n; i++)
	{
		M *= i;
	}
	return M;
}
int main()
{
	int n = 0;
	scanf("%d",&n);
	printf("%d\n",My_F(n));

	return 0;
}